Generally speaking, a linear amplifier provides an output that is linearly proportional to its input. Such a performance characteristic is important in many application settings such as, but not limited to, wireless transmissions. Unfortunately, many cost effective amplifier designs only exhibit substantially linear behavior over a portion of a corresponding operating range.
Various techniques are therefore known in the art to facilitate linearizing the performance of such an amplifier. One such technique can be referred to as Cartesian feedback linearization and provides, in part, for closed loop phase training of the amplifier. This training utilizes a Cartesian training waveform of known form and duration (which may comprise, at least in part, a sine wave).
Such an approach, unfortunately, can give rise to a certain amount of corresponding adjacent channel splatter during the phase training activity. This unwanted phenomena is becoming a source of greater concern as standards and specifications governing levels of acceptable splatter become ever more restrictive.
Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions and/or relative positioning of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of various embodiments. Also, common but well-understood elements that are useful or necessary in a commercially feasible embodiment are often not depicted in order to facilitate a less obstructed view of these various embodiments. It will further be appreciated that certain actions and/or steps may be described or depicted in a particular order of occurrence while those skilled in the art will understand that such specificity with respect to sequence is not actually required. It will also be understood that the terms and expressions used herein have the ordinary meaning as is accorded to such terms and expressions with respect to their corresponding respective areas of inquiry and study except where specific meanings have otherwise been set forth herein.